Conveyer furnace for heating metal sheets or plates



Oct. 6, 1936. l ALL 2,056,510

CONVEYER FURNACE FOR HEATING METAL SHEETS OR PLATES Filed March 6, 1934 s Sheets-Sheet 1 0a. 6, 1936.- FALLON 2,056,510

' CONVEYER AFURNACE FOR HEATING METAL SHEETS OR PLATES Filed March 6, 1934 3 Sheets-Sheet 2 "J. FALLON Oct. 6, 1936.

CONVEYER FURNAC E FOR HEATING METAL SHEETS OR PLATES s sheets-sheet 3 Filed March 6, 1954 I Patented Och 6, 1936 I UNITED STATES PATENT OFFICE CONVEYER FURNACE FOR HEATING METAL SHEETS OR. PLATES John Fallon, Birmingham, England Application March 6, 1934, Serial No. 714,258 In Great Britain January 24, 1934 4ClaimS- (01. 2636) My invention relates to conveyer furnaces for mal conveying speeds by means of a longitudiheating metal sheets, plates, packs, and like lamnal worm shaft (1 driven by a variable-speed priinated metal goods, more particularly the conmary motor e at the inlet end of the furnace, tinous or continuous-intermittent live roller type this motor 6 being operated by current passing of conveyer furnace for this purpose. from the mains at M and through a contactor In furnaces of this type, difliculties and inz normally closed by a coil 2 A variable pluconveniences have been experienced in connecrality of rollers a to a at the discharge end tion with the extraction of the goods when ready of the furnace is electrically adapted for an infor discharge and delivery to the rolling mill, termittent ejecting rotation at high speed by and it is the object of the present invention to means of an ejection motor 7. For this pur- 10 avoid these defects and to provide a roller conpose alternate rollers 01: a a (1 adjacent the veyer mechanism which shall be highly convendischarge end have insulated bearings and are lent and efiicient under varying conditions of coupled to the starting coil 9 of a switch It aroperation, both for the traverse of the goods ranged in circuit with the motor 1' of the disthrough the furnace and for their extraction charge door 7', with intervening control switches 15 therefrom at the discharge end of the furnace. k k k which serve toswitch in or out the num- The invention consists in a roller hearth conber of rollers required in accordance with the veyer furnace wherein the entire series of rolllength of the pack being traversed at normal ers are geared together for rotation at a unifurnace speed. The worm shaft d is fitted, in

form normal conveying speed, and wherein a positions adjacent the rearward rollers a to c0 2 variable plurality of the rollers at the discharge of the group of rollers to be speeded up, with end of the furnace are electrically adapted for a series of say three free-wheel clutches d of an intermittent ejecting rotation at high speed, the ratchet-type each having a ratchet wheel this high-speed discharge being effected by an d pawls d adjustable pressure devices d and ejection motor adapted either for automatic or a slidable locking dog d which clutches per- 5 push-button control, and being preferably armit of the ejection group of the determined numranged for operation in synchronized relation to her of rollers a to a being forwardly over-run the opening and closing movements of the disat high speed, in the same direction as the recharge door of the furnace. mainder of the rollers a, when the ejection motor In order that the invention may be clearly I is switched into circuit. 30 understood and readily carried into practice, ref- The several overrunning clutches d are used to erence is had to the appended explanatory drawpermit the number of rollers in the high-speed ings, in which:- ejection group being varied according to the- Figure 1 is a side elevation of a pack-heating length of the material carried by the rollers. furnace of the roller hearth type having the Material of short length will not require many 35 present improvements embodied. rollers to be run at high speed, while material Figure 2 is a sectional plan of the furnace. of greater length will require more rollers to Figure 3 is a diagrammatic side elevation ilbe run at high speed. When one clutch has been lustrating the electrical arrangements. set for the overrunning free-wheel action, the

Fig. 4 is a sectional side elevation of one of other clutches are locked by a sliding adjustment 40 the free-wheel clutches referred to below, while of the dogs d Fig. 5 is an elevation of said clutch, the last- The high speed ejection motor f is actuated mentioned view being taken in section on a plane automatically by the forwardly moving pack short indicated by the line V-V in Figure l, with a circuiting certain of the rollers. As the pack part of the slidable locking dog 11 referred to traverses forward, it successively makes bridg- 45 below broken away for facility of illustration. ing contact with adjacent pairs of the group of In a convenient method of carrying the invenrollers a to a coupled to the starting coil g, and, tion into effect, as applied to a pack-heating according to the setting of the control switches conveyer furnace of the roller hearth type havk k k current from a small transformer Z ing live rollers disposed transversely in paralconnected to the mains at M passes through the 50 lelly spaced relation from end to end of the furstarting coil 9, through the pack bridging the mace and having over and under firing, the rollselected pair of rollers, and is earthed through one ers a are built up on shafts b mounted in exor other of the intermediate rollers a a! a of ternal bearings c, the entire set of rollers being this group, this causing a switch 9 associated externally geared for rotation at uniform norwith the starting coil g to close, and thereby op- 55 crating the door motor contactor h by passage of a current from the mains at M through said switch 9 and through a coil q. This in turn operates the door motor i by current passing through said contactor h from the mains at M and opens the vertically sliding discharge door 9' of the furnace. The overhead control gear of this door 7' incorporates an arm a" carrying a double-ended knock-off contact 7' associated with a pair of switches m and 1'. On the door 9 reaching its uppermost position, said contact 7' closes the switch m, which in turn operates the coil n of a contactor o by current passing through said switch m from the mains at M This closes the contactor o and starts the ejection motor 1 by current passing through said contactor o from the mains at M causing the pack to be traversed forward at high speed, until on the pack making bridging contact with the terminal pair of rollers a and a current from the transformer Z is passed through a coil p, through the pack bridging said terminal pair of rollers and is earthed through the roller a This causes the coil p to open-circuit a stop switch p which open-circuits the maintaining coil q of the door motor contactor h. The door motor 13 is thereby switched off, the door i closes, and the contact 7' opens the stop switch 1 whereby the ejection motor 1 is thrown out of action.

For non-automatic ejection, a stop switch 8 in the starting coil circuit is opened, and a hand-com tro l push-button t is utilized for controlling the ejection of the pack. Depression of this button it causes the current from the transformer Z to go through the starting coil 9 and button If to earth, closing the starting coil switch 9 and operating the door motor contactor h, the subsequent sequence of operations being the same as already described.

Emergency stoppage of the entire plant is provided for by joint operation of an ejection motor emergency stop switch u and a primary motor emergency stop switch to having a coupling-bar connection v, these stop switches u and w being normally closed. On the switch w being opencircuited by the bar '0, the circut through the contacts 2 from the mains at M is open-circuited and the primary motor 6 is stopped. Simultaneously the switch it is open-circuited, this causing the circuit through the contactor ofrom the mains M to be open-circuited for stoppage of the ejector rn'otor f. Restarting is effected by depression of an ejection motor emergency starter as, causing the coil n to close the contactor o by passage of a current from the mains at M and by depression of a primary motor emergency starter 11 associated with the coil 2 and contactor z. The ejection motor contactor h is synchronized and interlocked with thedischarge door motor 11 so that it is impossible to eject the pack unless the door 7' is fully opened.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a conveyer furnace for heating metal sheets and the like, in combination a roller hearth, means for rotating the entire series of rollers at a uniform normal conveying speed, means for intermittently rotating a determined group of rollers at the discharge end of the furnace at a high ejection speed, and electrical means for initiating said high ejection speed by contact of the forwardly moving sheets with selected rollers at variable distances from the discharge end of the furnace.

2. In a conveyer furnace for heating metal sheets and the like, in combination a roller hearth, a drive shaft gearing the entire series of rollers together for rotation at a uniform normal conveying speed, means for intermittently rotating a determined group of rollers at the discharge end of the furnace at a high ejection speed, freewheel clutch mechanism interposed in said drive shaft for determining the number of rollers in said high-speed ejection group, and electrical means for initiating said high ejection speed by contact of the forwardly moving sheets with selected rollers at variable distances from the discharge end of the furnace.

3. In a conveyer furnace for heating metal sheets and the like in combination a roller hearth, an outlet door at the discharge end of the furnace, means for rotating the entire series of rollers at a uniform normal conveying speed, means for intermittently rotating a determined group of rollers at the discharge end of the furnace at a high ejection speed, electrical means for initiating said high ejection speed by contact of the forwardly moving sheets with selected rollers at variable distances from the discharge end of the furnace, and means whereby said high-speed discharge is operated in synchronized relation to the opening and closing movements of the outlet door.

4. In a conveyer furnace for heating metal sheets and the like, in combination a roller hearth, a drive shaft gearing the entire series of rollers together for rotation at a uniform normal conveying speed, means for intermittently rotating a determined group of rollers at the discharge end of the furnace at a high ejection speed, freewheel clutch mechanism interposed in said drive shaft for determining the number of rollers in said high-speed ejection group, electrical means for initiating said high ejection speed by contact of the forwardly moving sheets with selected rollers at variable distances from the discharge end of the furnace, an outlet door at the discharge end of the furnace, and means whereby said highspeed discharge is operated in synchronized relation to the opening and closing movements of said outlet door.

JOHN FALLON. 

